Pith Centered Board In Workbench

[James White]

I am in the process of milling some ash for a Roubo style bench. I have found that one of the boards is pith centered. Two others are near the pith. I am actually not sure were the pith technically ends. Do you count a certain number of rings from the center to determine what is pith and what is "good" wood? So my question is will using these boards adversely affect my bench top. The boards will be a minimum of 1.5" thick and a min of 3.5" wide and 96" long. I could replace these boards. However that may require that I splice some shorter boards to make up the 96". What would you do?

James

[Wilbur Pan]

If your boards are dry, and there's no cracking, you may be able to get away with it. But why would you take that chance? This workbench is something that you will be using a lot for a long long time, and now is not the time to cheap out.

I would just get new ash boards. Two 4" wide 8/4 ash boards that are 8 feet long is just over 10 board feet of lumber.

[Tom Veatch]

... What would you do?

Use it.

If the pith is centered in the board, ignore it. If the pith is on or close to one surface, orient the board in the assembly so the pith is farthest from the work surface. Then glue up the assembly and think no more about it.

[John Schreiber]

On a big structure like a 3 1/2" thick workbench top, it probably won't make a bit of difference. But for something which is going to be in use forever, it might be worth it to get it perfect.

Regarding pith, I'm usually happy if the actual pith is not in the lumber, but for maximum stability on thinner wood, I'd want even grain which would not be near the pith.

I'd probably do the splicing, especially if I could be sure it won't be too visible and the spliced board is not near the edges. Your call

[James White]

Thank you for your input guys. I am still unclear as to what constitutes the pith vs good wood. Any one care to enlighten me? Is it species dependent, age of the tree diameter from the center.

James

[John Keeton]

For what it is worth, every time I have used anything close to the pith I have regretted it. Maybe it is just my luck!

James, on your question, I think to a degree it is species dependent. Some woods seem to want to move terribly bad near the pith - others not so much. I haven't used ash that was center cut before, so couldn't say on that.